SQL Server 2008：在尝试通过连接访问数据库的CLR函数时出现异常

I want to use CLR table-valued function in SQL Server 2008, which accesses a database from inside itself. I've got a permission exception. I am trying to execute function as the same user as under which it was created. So cause of the problem is not clear..I want to use CLR table-valued function in SQL